okay...I'm trying to go to the dyno tomorrow, and I have this problem...so I really need some quick help.
Initially, the car would start to stumble around 3500rpm and fall flat on it's face at 4000rpm under boost. At no boost, it will rev to redline fine. I regapped the new spark plugs to .035 (they were .040), and it delayed both events about 500rpm. This is all going on with a wideband sensor in the car, so I'm pretty sure it's not running too lean, or too rich.
So far, I've checked the wires...max resistance was 18k ohm. I cleaned the dizzy cap and rotor, swapped the coil to another that I know is good, and switched from the HEI module back to the nissan module. The plugs are brand new, and all look fine. My advance map doesn't do anything out of the ordinary in that range. I'm all out of ideas. Any help would be great.